Tweaks.

Author: microbit-robert

src/board/sensors.ts

@@ -130,7 +130,7 @@ export interface LogData {
 }
 
 export class DataLoggingSensor extends Sensor {
-  public value: LogData[][] | null = null;
+  public value: LogData[][] = [];
   public period: string = "none";
   public delete: boolean = false;
   public serial: boolean = false;

src/board/ui.ts

@@ -700,6 +700,6 @@ export class DataLoggingUI {
     this.log.serial = false;
     this.log.period = "none";
     this.logData = [];
-    this.log.setValue(null);
+    this.log.setValue([]);
   }
 }